Well, there are a few things that could be wrong:

a) Dodgy files, the files you downloaded may be fake or corrupt.

b) Codec, you don't have the proper codecs on your computer. Try using the VLC media player, it is very good and can play most media files.

VideoLAN, Free streaming and multimedia solutions for all OS!

C) Check if your PC is OK, trying playing this YouTube file (I was listening to while reading your post):

http://www.youtube.com/watch?v=jgkhThEMRr8



UK Bob